                   (case k
                     :iso-format (.format DateTimeFormatter/ISO_LOCAL_DATE_TIME ldt)
                     :format     (.format (dt-formatter v) ldt)
-                    :instant    (.toInstant ldt ^ZoneOffset (or (zone-id v) @system-zone))
+                    :instant    (.toInstant ldt (or (zone-offset v) @system-offset))
                     :julian     (julian-field ldt v)
                     :local-time lt
                     :local-date d


        {`p/nav (fn [_ k v]
                  (case k
                    :format (.format (dt-formatter (or v "yyyy-MM")) ym)
                    nil))})))


(defonce ^:private system-zone
  (delay (ZoneId/systemDefault)))

(defonce ^:private system-offset
  (delay (ZoneOffset/systemDefault)))

(extend-protocol p/Datafiable

  Month
